I am almost done fixing up a building I will be doing my work in. The only thing I have left is to make a place for my forges exhaust. I have my forge but Want to know where to put the chimney. Should it go through wood with insulation or the tin roof? What kind of insulation do I need between the wood and stovepipe or roof tin, and what kind of material do I need for the pip itself?

If you didn't know, I love stainless when I can get it, so I do have some stainless pipe. Would that be ok? 6' is all I have left but I can get more (It would get me to the wall or roof)

Opinions?

What does the code FOR YOUR AREA require for a chimney through a roof? Always a good place to start. Forge chimneys are usually cooler than woodstove chimneys.

Out the wall and then up chimneys tend to work well in places that get a lot of rain as you don't have to pierce your roof.

When I roofed my shop extension I spaced the top purlins so I can stick a 12" pipe between them (all steel so not an issue with heat). The peak is a bit easier to deal with in my opinion; but I am in dry NM and so haven't even put a ridge cover on it yet ventilation is a *good* thing out here where I have been wearing short sleeves for over a month!

I would go for the roof, you'll get better draft and you won't have to deal with the fire issues as much. I also expect you'll want something more than 6" pipe. 10 or 12" is more suitable for a forge. Remember that you're forcing air through the fire, so you are burning a lot more fuel than the size of the hearth would indicate. I've seen several folks talked into 6" stovepipe by the heat-and-air guy or sheet metal place and then have to replace it with something bigger a few months later when they realize it can't handle the smoke.

Lewis

I don't know about a code for a shed, lol. I'll ask at a stove store down the road. (I've checked about insulation there before , nice stuff but expensive)

My forges chimney in the top measures 6" X 4". thats why I have a 6" pipe. But I can buy larger.


Thanks

I just installed a smithy with an overhead hood and 8" exhaust. ... It does not work well. It's fine for the wood stove but not for the forge. I am getting prices and will order 10" exhaust pipe and will go with the Hofi style side draft super sucker . Look for the subject here in IFI (see BP1048 Side Draft Chimney). The pics posted by one of us on the matter of the side draft are quite an argument to go down that road (http://custerfamilyfarm.com/blog1/index.php?blog=4&title=oh_the_finishing_of_the_forge&more=1&c=1&tb=1&pb=1#comments).

...
After lookin at your pics, I believe my comment is out of place.

I saw the small opening on your forge 'hood'. However, I know from experience that 6" pipe won't even handle the start up of my little hand-cranked riveter's forge. That top might have been designed to work with a powered exhaust system rather than natural draft.

I am almost done fixing up a building I will be doing my work in. The only thing I have left is to make a place for my forges exhaust. I have my forge but Want to know where to put the chimney. Should it go through wood with insulation or the tin roof? What kind of insulation do I need between the wood and stovepipe or roof tin, and what kind of material do I need for the pip itself?

If you didn't know, I love stainless when I can get it, so I do have some stainless pipe. Would that be ok? 6' is all I have left but I can get more (It would get me to the wall or roof)

Opinions?

Hi A, I would either find some double walled ss flue pipe from a stove manufacturer and stick it straight up through the roof or I would angle it upwards and out through the tin wall. Obviously keep any un-insulated pipe well away from any wood (at least a foot away). Hope this helps, DM

Thanks for the replies ,.

I don't know much about my forge I would love to get some history on it but alas I have found none. The blower is marked Lancaster geared blower NO40. ALSO, Champion blower & forge CO Lancaster, PA, U.S.A.

Point being I think its decently old (poss before exectics, at least in a BS shop), do you think it was made for a powered exhaust. If so I would get one. I LOVE OVERKILL lol.

Would anyone think that I should take the cover off and get a hood and a 10" or 12" pipe. If I'm spending money I might as well go deep lol.

some pics.


Bad pic of building. Before I started cleaning it out.

Hoods, even excessively large ones, don't work as well as a side draft unit.

The walls of my shop are made from the hail damaged "tin" roof off a friend's house and for my small coal forge I stuck a piece of 10" spiral seamed duct work through the hole already there from his woodstove chimney.

Considering I still want to use my current forge would ya'll see a way to take my hood off and make a side draft unit for it? Just googled it and found that they look nothing like my setup.

Would anyone be kind enough to sketch out a rough sketch or small design, or show a pic of a setup they think would apply to me. (ms paint maybe)


"Have ye pen and pad"

I think that you could just buy a standard 4"x6" reducer from 12" round spiral duct and go straight up through your roof with a chimney thimble. That would give you a 2" air gap from contact with any other material, a boot to conform to the corrugate roof, then you would need at least another two feet for a stack and a collie cap for the stack. The collie cap will need to be above the stack two times the diameter of the stack, 24". Did all that make sense to you? If I knew shineola about a computer I could draw you a picture but since I don't I won't. :blink:

Makes sense. I'm going to the supply house this Saturday to see what I need for insulation and the roof. I keep checking for input before I finalize my build.


Possibly there will be pictures. ;)

I looked at your forge cover and it's rather unusual. It looks shop-built; it's made from plate connected with riveted straps, while your forge is mostly cast iron. If someone built it later, it could have been for a special purpose or just a bad idea. That's a nice big blower and a nice big tuyere, so you're gonna need more exhaust than 4x6 inches based on my experience. It is possible that a larger pipe will have enough draw to suck all the smoke through the smaller opening. A lot of side draft exhausts have a smaller opening than the flue size.

Huh. The upper part of your cover is cast iron. I'm out of ideas, but I still don't think it's original to the forge.

All of the part shown that is rusty colored except for the sheet metal straps holding the two sections together are cast iron. The hinged section is cast iron, the section with the flue connection is cast iron and the bottom section where it sits on the main body of the forge is cast iron. This apparatus reminds me of a gas fired heat treating forge that was for sale at a scrap yard here in Phoenix a few years back except that this one looks to be coal or coke fired. I just don't see the plate steel in this piece of equipment. :blink:

Huh. The upper part of your cover is cast iron. I'm out of ideas, but I still don't think it's original to the forge.

Bentiron, I retracted it in the same post. My mistake if I wasn't clear.

I'm still not sure if the part with the slots (attached to the bottom of the straps) is cast or plate. It did look kind of oven-ish to me too, but I'm still not convinced it's original to the forge or that the cone and lid went with the lower section attached by the straps. Kinda Frankenstein looking. :unsure:

Very Cool! I'll Try to build one in. Thanks for the links .

Its all cast iron a little thicker than 1/2". the top matches the rest of the forge in material and thickness. Its rusty because the pictures were of the first day I got it.

I'll put a few more.


I love the look of the side draft. Can't wait for the trip tomorrow. I'll price it all out, give my design and see what y'all think.



35lb rock hammer lol.

It reminds me of some of the rivet heaters used in construction back in the day. You wanted the fire contained and not dropping hot coals 16 stories down on the building inspector...